This invention relates to curable epoxy resin compositions which are cured with a vinyl polymer hardening agent having pendant isocyanatoalkyl ester groups.
Coatings based on epoxy resins provide good solvent resistance, hardness, adhesion and the like and are therefore widely used as coatings for a wide variety of substrates such as metal, wood, plastic and the like. Unfortunately, however, such coatings are noted for their tendency to yellow and chalk when exposed to ultraviolet light and other weathering conditions.
This yellowing tendency is particularly evident when amines, such as diethylenetriamine and the like, are used as curing agents. Accordingly, epoxy resin compositions, wherein the problems of yellowing, chalking and other deterioration caused by exposure to light are minimized, have been pursued by the coating industries for a substantial period of time.
In view of the aforementioned deficiencies of conventional epoxy resin compositions and the desire of the coating industries to employ epoxy resin compositions free from such deficiencies, it is highly desirable to provide a hard, adhesive, solvent-resistant coating based on an epoxy resin which exhibits increased resistance to degradation upon exposure to ultraviolet light and other conditions common to the environment.